WILLIAMSTOWN — Two pugs perished in a Sunday afternoon chimney fire that destroyed an old house on Pleasant Street and left its lone occupant homeless heading into the new year.

A passerby, who was described by officials as a neighbor, spotted smoke, summoned firefighters and alerted homeowner Harold Brown that his house was on fire shortly after noon Sunday.

Brown and one of his three dogs made it safely out of an adjoining structure, before the house was gutted by fire over the span of several hours and ultimately toppled by an excavator.

Due to the age of the century-old two-story home and the nature of the construction, Assistant Fire Chief Tim Emmons said the mix of volunteers and professional firefighters who responded from seven area departments didn’t have many options.

“We couldn’t effectively put the fire out with the house still standing,” Emmons said of the decision to call in the excavator Sunday evening.

Though the fire was deemed under control by 6 p.m., Emmons said the home was heavily damaged and structurally undermined — effectively forcing firefighters to abandon their interior attack.

Capt. Chris Eaton echoed that assessment, explaining that when fire spread from the home’s second floor to a basement filled with a winter’s worth of wood — some of which was actually providing structural support for the first floor — it was time to pull out.

According to Eaton, when firefighters arrived there was heavy black smoke coming out of the eaves of the house and flames were soon visible at the rear of the structure.

At that point, Eaton said, firefighters went into the home and recovered a number of Brown’s personal belongings, including the two dogs that died, and tried to douse the fast-spreading fire.

“The whole upstairs was burning from one end to the other,” he said, noting there was ample fuel for the fire throughout the home.

“It just wanted to burn,” he said.

Williamstown firefighters were joined at the scene by volunteers from Barre Town, Berlin, Brookfield, Chelsea and Northfield, as well as members of the Barre City Fire Department.

Emmons said it appeared the fire started in the chimney. It is not believed to be suspicious, he said.

With his home reduced to an ice-covered pile of charred wood near the corner of Pleasant Street and Rood Pond Road, Brown is temporarily staying with a neighbor, said officials.